1. Field of the Invention
The present invention relates to a press-fit connector which can be connected to a circuit board such as a printed wiring board, and particularly relates to a press-fit connector enabling replacement and repairs of individual defective terminal or of a housing and a housing-remover tool for such a connector.
A rapid development in a connector known as a press-fit type used for an electronic apparatus or a communication apparatus has resulted in a finer pitch of pin-type terminal array and an increased number of terminals. Due to reduced diameter of pin parts of the pin-type terminals, a slight external force applied during processes such as press-fitting the connector to the circuit board, connecting the connectors and handling the connectors may cause various defects such as buckling, bending or breaking of the pin-type terminals.
In order to deal with such defects, it is often required to remove the connector from the circuit board. However, such a defect may arise during manufacturing of an electronic apparatus and also while such an apparatus is in operation. Therefore, there is a need for a connector enabling easy repairs and a tool for such repairs.
FIG. 1 is a diagram showing a general press-fit connector. A housing 1 is made of molded synthetic resin member and has a rectangular cross-section when viewed from the front. Pin-type terminals 5 are forced into a plurality of terminal through-holes 3 provided in a bottom surface 2 of the housing 1. Also, stepped parts 6 are provided in parallel on a pair of opposing edges of the bottom surface of the housing 1.
The pin-type terminals 5 are made of a metal such as phosphor bronze having high conductivity, mechanical strength and elasticity. The pin-type terminal 5 has pin parts 7 of small diameters at both ends in a vertical direction shown in the Figure, a shoulder part 8 provided at an intermediate part and having a great width, and press-fit part 9 formed as a ship bottom shape by a pressing process. The pin-type terminal is for example Au-plated and is secured to the housing 1 by forcing the shoulder part 8 into the terminal through-hole 3.
The circuit board 11 which may include a printed wiring board is provided with through-holes 13 formed at positions corresponding to the pin-type terminals 5. The conductive coating 12 is applied in the through-holes 13. When the press fit part 9 is inserted in to the through-hole 13, both sides of the bottom ship shape deforms in an elastically-compressed manner. The press fit part 9 elastically touches the conductive coating 12 by a recovering force to realize an electric connection. The conductive coating 12 is connected to a circuit pattern (not shown) of the circuit board 11. FIG. 1 shows a state just before the press-fit part 9 is inserted into the through-hole 13.
2. Description of the Related Art
FIGS. 2A and 2B are a plan-view and a transverse cross-sectional view in which it is insertion connected to the circuit board 11, respectively, of a connector. As can be shown in the figures, the shoulder parts 8 of the pin-type terminals 5 and the longitudinal direction of the press-fit part 9 align with the longitudinal direction of the housing 1, but is shown in an orthogonal direction in FIG. 1 for convenience of the description. Also, the pin parts 7 on the lower side of the pin-type terminals 5 are shown to be shorter than the upper pin part 7.
As shown in FIG. 3A, which is an enlarged view of a main part of the terminal through-hole 3 of the housing, the terminal through-hole 3 has a rectangular shape. Also, as shown in FIG. 3B, which is an enlarged view of a main part of the pin-type terminal 5, the shoulder part 8 has a rectangular cross-section extending in a vertical direction of the figure. The pin part 7 having a square shape is positioned at the center thereof and the shoulder part 8 is configured such that its thickness (the horizontal direction in the figure) and its width the vertical direction in the figure) are greater than those of the terminal through-hole 3. Accordingly, the pin 5 is secured in the terminal through-hole 3 after being forced therein.
FIG. 4 is a cross-sectional diagram showing various possible defections of the connector. In the figure, “A” shows a state where the pin-type terminal 5 is bent by buckling of the press-fit part 9. “B” shows a normal state where there is no defection of the pin-type terminal 5. “C” shows a state where the pin part 7 of the pin-type terminal 5 is bent. “D” shows a state where the pin part 7 of the pin-type terminal 5 is broken. “E” shows a state where there is deformation or a defect at a part of the peripheral wall of the housing 1.
The state “A” may arise during a process of press-fitting the connector to the circuit board 11. The state “C” may arise when the mating connector 15 is inserted while there is an inclination of the pin-type terminal 5 in the stat shown in FIG. 2B. The state “D” may arise when attempting to pull and remove the connector from the state “C” and the bent part is cut. The state “E” may arise by improper handling of the connector. In practice, for the states “C” and “D”, the bottom surface of the housing 1 is in contact with the surface of the circuit board 11. The state shown in FIG. 4 may arise due to various causes described above, but are illustrated in the same figure for the sake of convenience.
For the state “A” described above, the housing 1 must be pulled and removed since the bent press-fit part 9 is tucked between the housing 1 and the circuit board 11. However, in order to pull and remove the housing 1, other pin-type terminals 5 that are already press-fit to the circuit board 11 may also be pulled with the housing 1. This is due to the fact that the pin-type terminals 5 forced into the housing is held with a resistance force against a pulling force of approximately 10N per pin.
When the housing 1 is pulled by engaging some kind of a tool at hand to the stepped part 6, a secondary defection such as half pulled out state of other pin-type terminals 5 press-fit to the circuit board 11, deformation of the press-fit part 9, bend of the pin part 7.
In the state “C”, if one attempts to pull the tip of the bent pin part 7 by clamping with a tapered pincher, the pin part 7 may be cut and give rise to the state “D”. In the state “D”, as has been described above, the housing 1 must be removed by clamping the shoulder part 8. Although it is possible to clamp the shoulder part 8, in removing the housing 1, there are problems as has been described above.
When dealing with the state “E”, when one attempts to replace the housing 1 only, there are still various problems as described above.
From the foregoing, press-fitting of the connectors to an apparatus is feasible at the factory but is substantially difficult or impossible for an apparatus in operation since it eventually requires replacement with a new connector.